Vapor generator or boiler



Nov. z5, 1941. G, WNSCH l 2,263,687

VAPOR GENERATOR OR BOILER Filed May e, 193e 2 sheeis-sheet 1 /nvenon'Guido Wnsch,

f/ ma,

Nov. 25, 1941. v

G. WNSCH VAPOR GENERATOR 0R BOILER Filed May e, 1959 2 Sheets-Sheet 2imanes.iat-;22s,4 1941 l UNITED STATES vPlrra-N11* OFFICE VAPOR'GENERATOR 0B BOILER -4 Guidofwnsch; Berlin-Wannsee' Germany, as- Isignor to Askana-Werke A. G., a corporation orGermany .Application Thisinvention rentes u', that generator or boiler 'which includes a waterreser. voir at o'r 'towards the end -of the vaporising section.v y

The operation or'foncefthrougW-or through flow -vapor generators orboilers Aoi. the usualconstruction, introducesv the diiiiculty that inpractice itis not possible" so to balance the quantity of feed water tthel heating ofthe furnace that lth'esteam producedhas the desired.tem-L 'p erature.v Every small variation in thefstoking -ofthe furnace,'everyiluctuation in the steam pressure and every' change in thefeedfpressure destroys the .equilibrium of the operation, and

value,'and the consequent increase in tempera- .ture of the steam, raisethe resistance to iiow in the steam section of the boiler thus reducingMay s,"1ss9;ser1a1 No.. 272,249 Germany May 71938 1s claims. loi.12a-451)- kind of vaporA 'does not affect the water content of the steamat the endof the vaporization section and thus the eflective-lengtlfi ofthe superheater of the boiler. Y

These defects are to some degree removed byv the :provision of a waterreservoir'in theboiler o r generator at or towards the end'oi theVaporizing section, as has previously been done.

In some of the boilers of this kind, however,

Water -level regulators were provided for controlling the feed such thatthe level of the water in the-'reservoir remained constant, the excessconserved water ilowing away or .being returned to the feed pump.

In another prior propbsal the inventor caused the varying ofthe waterylevel in the reservoir by a steam-temperature-responsive control of adischarge conduit and in such a way that a. greater the amount of feedwater which can be admitted.

'This produces a still further increase in the steam temperature, sothat these usual generators or vboilers are liable to a certain amountof-in stability. l

In these .earlier generators or boilers an even greater drawback is metwith, viz. that the conf trolof the quantity of feed water, which is forexample effected by a temperature and/,or load regulator. can only beeffected with a large degree f of lag.'-

unexplained, it is'in-practice-impossible to control the-operatingconditions in the boilermerely by. regulating the supply of-ieexiwater,as

,theoretically shouldbe possible.y ,When 'varia-Y tions occur in theload, the, lag in theeiect produced by the increase ofleed water resultsin an undesirable displacement of the zone of conversion in the boiler,i. e. avariation in the. length of the .superheater and a uctuation invthe steam temperature. On the other hand` i! regulation, which is'theoreticaliyconceivable and is regarded, as a particular advantage cionce. throughtboilers, practically useless. Experience has indicatedthata regulation ofl the vfeed water In view of filling-up or congestionprocesses which take place in the vaporizing section of the boiler, andwhich' are still partly'v or smaller portion of the. collected water wascarried away by the steam and thus regulated the temperature of thelatter. 'This form of regulationof the steam temperature has thedrawback that the amount of water carried off` by the steamis dependenton vthe water level in the container. However, this waterlevel only'varies comparatively slowly when the discharge conduit is regulated, andthe smaller the\degree of excess feedthe slower the change in the waterlevel. In the case of the boilers without an excessl feed, this useless.

Thus the-quantityvof conserved water which` is carried oif by the steamfor cooling the latterv is only eii'ective a considera-ble time''afterthe steam temperature has altered, this lapse of time beingl stillgreater as the. excess feed to th boiler-iss'maller.

Inaccordance with this invention there is provided a through flow boilerincluding a tubudischarge conduit Ileading into the said tubularvaporizing system of' the boiler, water 'discharge regulating means forsaid discharge conduit, and steam temperature sensitive means disposedso as to be -respon'sive't'o the temperature of the steam produced bysaid vaporizing section of the boiler and adapted tocontrol theregulation of .the said water dischargedregulating means.

'Thus the water in the reservoir is not, in this invention, carried of!bythe steam in an amount coi-related to the temperature-dependent waterlevel, .as in the aforesaid prior proposal, but is method otregulationis entirely complexity .added directly to the `steam through the tem'-temperatureimpulse without any time delay and v independently of thedegree .of over-feed. Thus the invention is also applicable for use withboilers which only operate with a small excess feed sumcient fornavigation purposes, and in boilers of this nature it is only by using4the present invention' that it is possible to obtain a regulation of thesteam temperature which is independent of the above-mentioned"filling-up" phenomena.

A further advantageis secured by using the present invention.Once-through boilers normally have avery small feed capacity which, inthe main, is determined bythe quantity of lboiling water in relation tothe steam produced. per unit time. The additional' quantity lof waterpresent in the reservoir, which for example is 1/2% of' the output perhour ensures a suiilcient feed capacity for the majority of purposes.

The conserved water can be added to the steam by arranging that thelevel of the water in the reservoir is above the part'at which thedischarge conduit opens into the part of -theboiler beyond thereservoir. Alternatively a drop in flow pressure which is present (andwhich may be artificially increased) between the reservoir and theopening of ther discharge conduit into the boiler can be utilized.'I'his latter arrangement has the advantage that a quantity o'f waterproportional to the quantity of steam owing is automatically withdrawnby suction from the discharge conduit.

.The reserve watermay be supplied to the boiler tubular system in asteam cooler of suitable constructiom'but preferably one in which theseparation of water is effected by a centrifugal action. This enablessalts to be deposited from ,separator 2,

The boiler is continued beyond the water separator 2 in the form of atube 8 of looped shape,

the lower bend of thi loop being located at a lower level than the ttomof the separator 2D This tube 8 includes a Venturi nozzle 9, and adischarge pipe I0, connected to the bottom of the communicates with thisVenturi nozzle.

A valve II inserted in the line I0 controls the flow of liquid in thelatter, and this valve II is adapted to be adjusted by the piston ofaservomotor I2. -The two sides of this piston are con- In thesedrawings, I designates generally the t vaporization section of aonce-through or push throng boiler or vapor generator and this sectionof the boiler is connected to a reservoir in the form of a centrifugalwater separator 2.

- ,'In the embodiment of the invention illustrated in Figure 1, thevaporizing section of the boiler is fed with water through a feedconduit 3 containing a main feed water valve 4. A second feed watervalve 5 is arranged in shunt with the valve 4, and the latter iscontrolled by a. servoinotor 4' which isgoperated by a feed waterregulator of conventional form,` the latter being omitted from thedrawings to avoid unnecessary Arranged in the separator! isa float lwhich is niounted on an arm pivotable about the point 8, v and thisfloat lis adapted to operate the valve l through a suitable mechanicalconnection, e. g.

5'. Alternatively .the valve i-could, of course, be .operatedby a waterlevel regulator which is de- `source controlling the valve.

nected by conduits Il-'and I4' to a temperature regulator I3 of knownconstruction. This regulator includes a thermostatic member I5 which isso arranged as to be subjected to the heat of steam leaving the boilerthrough a steam consumption line I6, whereby the member I5 enables thetemperature of thesteam as'it leaves the.

boiler to be estimated.

Finally, a superheated section of the boiler lies between the loop 8 andthe steam line I6,

The boiler which is described above with reference to Figure l oftheaccompanying drawings functions in the'following manner.

A part of the feed water required by the boiler passes thereto throughthe valve 5 in the shunt line. The control of the valve 5 exerted by thefloat 'I vin accordance with thev water level in the separator 2 is suchthat this levelv remains the same with the water at a. predeterminedheight.

A certain amount of water continually escapes from the separator 2,through the discharge pipe .I0 and the valve II-, into the tube 8 andthus affects the amount of water in the steam, i. e. theeiiective-length of the superheater section I1. As soonl as the steamflowing through the superheater I'I becomes too hot, the temperatureyregulator I3 opens the valve II and allows an increased quantity ofwater to flow into the tube 8. In the result, the water level falls inthe separator 2 and the iioat I consequently causes a corre-,spondinglyincreased opening of the-valve 5.

Since the separator 2 contains aconsiderable volume of water, it is ofno disadvantage if the effect of the extra supply of water to which thevalve 5 is set is not apparent in the separator 2 until some time haselapsed. The reserve of water leaving the separator 2, which reservedetermines the water content of the steam fiowing through the loop 8, ison the contrary immediately available, and in view of the comparativelysmall size of the superheater section I1, the steam temtively passedinto this loop, even if only quite a small quantity of steam is presenttherein.

The Venturi nozzle 9 produces a fall in the flow pressure in the pipe I0which is greater according as the vquantity of steam passing through thetube 8 is greater.

Referring now to Figure 2, the vaporizer I is here supplied with, waterthrough a valve I8 which is under the dual control of a servomotor I 8'of a feed water regulator (not shown), and a lever system I9 which isoperatively vconnected to the iioat l in the water separator 2. Thisdual control is eifected through a known form of sumi amasar.

mation leversystem denoted l2li in thedrawings.4

In contradistinction to the arrangement illus- 'trated in Figure 1, thedischarge pipe connected- -to the underside of the 'separator 2herecommunicates with a steam cooler 2| which is connected up betweentwo superheater stages I'| and II/'in the steam line. The cooler2|.-,com-

prises a spherical vessel into which a rectilinear extension of thevsuperheater I'I; openstangentially. The pipe I is also tangential to thecondenser 2| adjacent its point of connection thereto.v

vBy this means ari annular circulation oi water isset upin the condenser2 I, and the steam from the superheater I1 has to pass. through'this be-/fore it can enter the superheater stage II'I'. This centrifugal actionhas. therefore, the result 1,25

only dry steamf passes to the'superheater I1'.

The residual water which accumulates in the cooler 2|, and-which will ofcourse containvarious salts, can be drained. off, fromtime intime,through a valve-controlled sludge pipe `22.

As in the first embodiment described, a valve arranged in the, pipe Inand isteria-oued through aservomotor I2 by a temperature regulator I3. Y

Now neglecting the diilerence in level between the water separator 2 andthe steam cooler 2|, which difference can conveniently be made zero inconstructing the plant, the'pressur'e in the \cooler 2|, is less'than inthe separator 2 because l of the fact that the superheater which sets upa certain amount of resistance to the flow of the steam, lies betweenthem. 'Ihus the fall in pressure in the superheaterll also affects thevalve II through the pipe Ill.. -This fall in pressure is also however,a measure of thequantity of `steam flowing through the superheater I1and if the quantity of steam is doubled, a four-fold drop in pressureoccurs in the superheater I'I. Thus theV differential pressure eifectiveat thefvalve I I rises to the sameextent, so that a double quantity of-water entersthe condenser 2| if the valve II is not shifted.' 'I'husthe steam will automatically withdraw av proportionate amount of coolingwater through the unadjusted valve without any time lag. Consequently,the temperature regulator I3 has only' to compensate minor .and

slowly-recovering fluctuations when variations occur in the load. 1

Two further valves 23 and 24 are controlled by the float 1 in the waterseparator, 2. The valve 23 is located in an auxiliary discharge 'conduitI0' Vconnectingy the discharge pipe Il) to asuitable pressure stage in afeed pump 25 supplying water-through the conduit I to the boiler. Thevalve 24 is located .in an inlet conduit 28 which is branched oil?- thewater feed conduit. I

v is no longer required.

that a means iorprodncing the injection pressure What I claim is:

' 1.- A v through iiow. boiler including a tubular vaporizing system,. aWater reservoir arranged in the said vaporizing system, means -formaintainof the steam .produced by saidvaporizing sectionof the boilerand adapted to control the regulation of the said water dischargelregulating means.' 2. A boiler accordingto .V claim 1 wherein the saidWater separatingsteamcooler comprises a centrifugal separator.

3; A push-through boiler comprising a. tubular vaporizing system, .atubular superheatingsys-v tem, a water reservoir betweenand connecting.,

togetherthe vapori'zing and superheating lsystems, conduit means fordischarging water from the said reservoir into the *tubular system of?the boiler beyond the reservoir, valve means for regu-V 'latingl thedischarge of l water by said conduit means, a steam temperatureresponsive deviice adapted to control said discharge regulating valve.

' and means for maintaining the level of the Water in the said reservoirsubstantially constant.

4.` A through iiow boiler comprising a tubular vaporiaing system, avtubular superheating system, a Water reservoir betweenl and Iconnectingtogether the vaporizing and superheating sysin iront ofthe valve I8 andopens into the upper portion of' the separator 2. Immediately the waterlevel in the separator 2 becomes too high, the oat 1 opens the valve 23and permits water to flow back through conduit I0 to the feed pump 25.On the otherv hand, if the water level fallsv too far, the valve 24 isautomatically opened and the reserve of water in the separator 2 isimmediately supplemented via the conduit 2B.

The valves 23, 24 and I8 can of course, be

otherwise controlled, lfor example by means oi.

water level regulator -with'a'n auxiliary source of power. A waterlevel-diilerential pressure system can be used for controlling the waterlevel regulator.

An evaporator cooler of known construction ein be used 1n place or thecomer zi wan its centrifugal separating construction. The use of 4atemsfconduit means for discharging water from the said reservoir in tothe tubular system of the boiler beyondthe reservoir, valve means forreguyIating'the discharge of water bysaid conduit means; a steamtemperature responsive device adapted to control. said dischargeregulating valve, a feed water regulating valve associated with the feedwater supply system, and means responsive to the level of water in thesaid reservoir and adapted to effect a variation in said feed Waterregulating-valve on a variation of --said reservoir water leveloccuring. A

5. Al through flow boiler comprising a tubular vaporizing system, atubular superheating system, a Water reservoir into which the saidtubular vaporizing system discharges, an auxiliary feed water supplyline in shunt with the main feed water supply line, a main feed waterregulating valve in the main feedV line, an auxiliary lfeed lwaterregulating valve inthe said auxiliary line,

feed water regulator means controlling the ,said

main ieed water regulating valve, afloat in said reservoir adapted tocontrol said auxiliary feedv water regulating valve in accordance withthe level oi the water in the reservoir. a looped steamtube leadingvfrom the steam space of fthe said reservoir to the said superheatingtubular system, a water discharge conduit leading from the'- saidreservoir to the said looped steam tube and communicating with thelatter, the said looped steam tube having its lower bend below the levelof the bottom of the said reservoir, and the said water dischargeconduit entering the looped steam tube at a level lower than that atwhich it leaves the said reservoir, 'means adjacent the entry of thesaid'waibr discharge'conduit into ,A y 3 condenser instead off'theerstwhile usual injectornozzles for the cooling water has the advantagethe looped steam pipe to ensure a fall in steam ing valve in said waterdischarge conduit, means for operating this valve, and a temperaturesensitive device disposed soas to be responsive to the temperature ofsteam at thev end of the tubular superheating system of the boiler andadapted to control the said Water discharge regulating valve operatingmeans.

6. A through flow steam generator comprising a tubular vaporlzingsystem, a tubularsuperheat- 7ing system, a water reservoir into whichthe said tubular vaporlzing system discharges, an auxillary feed watersupply line in shunt with the main feed Water supply line, a main feedwater regulating valve in the main feed line, an auxiliary feed waterregulating valve in the said auxiliary line, feed water'regulator meanscontrolling the said main. feed Water regulating valve, a float in saidreservoir adapted to control said auxiliary feed water regulating valvein accordance with the level of the water in the reservoir, a steam tubeleading from the steam space of the said reservoir to the saidsuperheating ing from the said reservoir to the said steam tube andcommunicating with the latter, vnieans adjacent the entry of the saidwater discharge conduit into the said steam tube to ensure a -fall insteam pressureat this position below the pressure within the saidreservoir, a water discharge regulating valve in said water dischargeconduit, means for voperating this valve, and a temperature sensitivedevice disposed so as to be responsive to the temperature of steam atthe end of the tubular superheating system of the boiler and adapted tocontrol the said water discharge regulating valve operating means.

7. Apparatus for controlling the operation of a vapor generator having aonce-through vapor passage receiving liquid at one end'and deliveringvapor at the other end, comprising in combination a liquid separatorarranged in the zone of evaporation vof said passage, means formaintaining the liquid level in said separator substantially constant, aliquid discharge conduit leading from a point below ,the liquid ,levelin tubular system, a water discharge conduit leadrator so as to causethe separater'. liquid to be drawn through said liquid dischargeconduit.

12. Apparatus for controlling the operation of a Napor' generator havinga once-through fluid passage receiving liquid at one end and delivervingvapor at the other end comprising in comliquid discharge conduit leadingfrom a point below the liquid level in said separator to the vapor partof said passage, liquid discharge controlling means 'for said dischargeconduit and means responsive to the temperature ofthe vapor in saidvapor part of said passage for actuating said liquid dischargecontrolling means.

13. Apparatus for controlling the operation of a vapor generator havinga once-through fluid passage receiving liquid at one end and deliveringvapor at the other end comprising in combination a liquid separatorarranged in the evaporation zone of said passage, a liquid dischargeconduit leading from a point below the liquid level of' said separatorto the vapor part of said passage, liquid discharge controlling meansfor said discharge conduit, means responsive to the temperature of, thevapor in the vapor part of saidjpassage for actuating said liquiddischarge controlling means,` first liquid supply control 14. Apparatusas set forth in claim 13 includv ing additional means for automaticallysupplying make-up liquid directlyl to said separator if the liquid leveltherein 'falls below a predetering additional means for automaticallydischargsaid separator to the vapor part of said passage,

'liquid discharge controllingmeans for said discharge conduit and meansresponsive to the temperature of the vapor in the vapor part vof saidpassage for actuating said liquid discharge controlling means.

8. Apparatus as set forth in claim 7 in which the mouth of saidliquiddischarge conduit is disposed at the 'same or at a lower level than themean liquid level in said separator.

9. Apparatus as setforth in claim 7 in which the m'outhof said liquid'discharge conduit is disposed at a point of the vapor part of saidpassage at which the pressure due to the pressure drop in said passageis smaller than the pressure in said separator.

. 10. Apparatus as set forth in claim 7 in which the mouth of saidliquid discharge conduit `is arranged at a pressure reducing devicedisposed in the vapor part of said passage beyond said separator so asto cause the separated liquid to be drawn through said liquid dischargeconduit.

ing liquid through an additional liquid discharge conduit from saidseparator if the liquid level therein rises above a predetermined value,

16. Apparatus as sei-,forth in claim 13 including a float in saidseparator', a liquid supply control valve actuated in joint response tothe movement of said float and to a liquid supply regula'tor, an excessliquid discharge 'conduit connecting said separator to the liquid supplycontrol means, a control valve in said excess conduit connected to beactuated by said float so as to be opened if the liquid level risesabove a predetermined value, an auxiliary liquid supply conduit leadingto said separator from said liquid supplymeans, and a valve in saidauxiliary conduit connected to be actuated by said float so as to beopened in accordance with the fall of the liquid level in saidseparator.

17. A vapor generator of the forced passage type having a once-throughiiuld passage receiving liquid at one end and delivering vapor at theother end, said passage including a vapor generating section and asuperheating section, said latter section consisting of two successiveparts, a rst liquid separator arranged between and connecting said vaporgenerating section and said superheating section, a second .liquidseparator arranged betweenand connecting the A 2,263,687 two parts ofthe 'superheating section, a liquid discharge conduit leading from apoint in said first separator below the liquid level therein to saidsecond separator, liquid discharge controlling means for controlling theliquid flow in said discharge conduit, and means responsive to thetemperature of the superheated vapor at the end of the superheatersection for actuating said liquid discharge controlling means.

18. Ayapor generator as set forth in claim 17 including in addition amain supply conduit for supplying liquid to said",y vapor generatingsection, an excess liquid discharge conduit connecting said flrstseparator to said supply conduit.

float means in said rst separator, valve means for controlling the ow ofliquid in said discharge conduit Aand connected to4 be actuated by saidoat means so as to lbe opened if the liquid level in said separotorrises above a predetermined value, an `auxiliary liquid supply conduitleading to said rst separator from said main conduit and a valve forcontrolling the iiow of liquid in said auxiliary conduit operativelyconnected to be controlled by said iloat means so as to be opened inaccordance with the fall of liquid level in said separator.v

GUIDO WNSCH.

